Open Access Open Access  Restricted Access Subscription or Fee Access

Polymer Nanocomposite for Strain Resilient Solder



Commercial off the shelf (COTS) electronics generally are not specifically designed to perform in extremely transient high impact scenarios. In these specific scenarios, the interconnect materials in electronic packaging undergoes through high strain rate (high-g) inducing severe degradation of the materials properties, dramatically limiting the device performance. Traditional interconnect materials (e.g. Pb-Sn solder) suffer from limited performance life under high strain rate and gradient. In this study, we have developed a high performance high strain rate resilient compliant solder. In order to develop the polymer solder to be strain resilient in its normal application temperature, the polymer system should have the glass transition temperature (Tg) significantly lower than the operating temperature. In this research, a series of the epoxy polymers were successfully made and the Tg of the polymer can be tuned and controlled by tailoring the concentration and the composition of the epoxy resins and the curing agent. Although the cross-linked elastomeric polymers are generally flexible and shock absorbing, they are electrical insulators. It was reported that the dispersion of the carbon nanotubes into the polymeric matrix can significantly improve the electrical conductivity to 10-5 - 103 S/m. However, this is still far away from the desired electrical conductivity for the solder materials replacement. Here, we report that the 20 wt. % MWCN/Epon 828/D2000 nanocomposite was successfully fabricated. Its morphology was investigated by SEM and TEM nanotubes were well connected to form a network. Initial measurement via van der pauw showed that the electrical conductivity of the nanocomposite could potentially reach to 2 x 104 S/m. The combined electrical-mechanical testing based on the test of the Split Hopkinson Pressure Bar (SHPB) showed excellent durability and small changes in electrical conductivity of this CNT/epoxy nanocomposite during the dynamic SHPB test.

Full Text: